Coccidioidomycosis is a fungal disease characterized by a cellular immune defect. In contrast to depressed T lymphocyte responses, patients with this disease show a B cell hyperplasia with increased serum of IgG, IgA, and IgE. Total IgE serum levels correlate with immediate wheal and flare responses which, in turn, correlate with anti-Coccidioides IgE antibodies. However, IgE responses are not limited to C. immitis antigens, but rather are demonstrable against a number of common allergens. Total serum IgE levels do not differ in patients with active coccidioidomycosis versus those with inactive disease. However, the results of assays for anti-Coccidioides IgE antibodies, although limited to a total of 13 patients with active disease and 6 patients with inactive disease, inicate that IgE antibodies to C. immitis are highest in patients who are in clinical remission. These results suggest that anti-Coccidioides IgE antibodies may play a protective role in this disease.